摘要
作用于H^+—ATP酶复合体质子通道的能量传递抑制剂 TPT、DQCD和 OM能明显抑制叶绿体光合磷酸化反应和膜上 ATP酶活性,减小恒态ΛpH值,加速ΛpH和515 nm吸收衰减。这种在正常叶绿体加速H_(in)^+经CF_0外流与在残缺膜中阻塞质子外流不一致。TPT等物质是干扰了CF_0与CF_1的构象连接,使 CF_0的质子传导失去CF_1的控制,H_(in)^+无效漏失或质子逆向转移受影响,从而抑制与质子传导紧密相关的光合磷酸化反应和膜上ATP酶活性。
Energy transfer inhibitors triphenyltinchloride(TPT),dicyclohexylcarbodiimide(DCCD) and oligomyin (OM), which act on theproton channel of H^+-ATPase complex, obvious-ly inhibit the photophosphorylation (PSP) reac-tion and the activity of membrane-bound Mg^(2+)-ATPase activated by DTT-light in chloroplasts.Their inhibition characteristics are different (Fig.1,2). They all decrease the steady state mag-nitude of ΔpH and accelerate the decay ofΔpH (Fig. 3, 4) and electrochromic absorption(Fig. 5, 6), indicating that they accelerate H_(in)^+efflux through CF_0. DCCD inhibits the basal,uncoupled and coupled state electron flow (Fig.9), while TPT and OM inhibit the coupled elec-tron transport only (Fig. 7, 8). This means thattheir accelerating effect on H_(in)^+ efflux is differentfrom uncoupling action. The conformational interaction between CF_0and CF_1 was discussed. It was suggested that theexistence of CF_1 controlled the conformationalstate of CF_0, and TPT, DCCD and OM inter-fereed with the conformational link between CF_0and CF_1, accelertaed the ineffective leakage ofH_(in)^+ or blocked the reverse transport of H^+through CF_0, hence the PSP reaction and mem-brane-bound ATPase activity were inhibited.
基金
国家自然科学基金
关键词
叶绿体
三苯基锡
CF0-CF1
chloroplasts
H^+-ATPase complex
proton conduction
energy transfer inhibitor
triphenyltin chloride
dicyclohexylcarbodiimide
oligomycin
interaction between CF_0 and CF_1
